The present invention relates generally to refrigeration and heating systems and more specifically relates to an apparatus driven by a Stirling cooler and having a heated area and/or a cooled area.
Known refrigeration systems generally have used conventional vapor compression Rankine cycle devices to chill a given space. In a typical Rankine cycle apparatus, the refrigerant in the vapor phase is compressed in a compressor so as to cause an increase in temperature. The hot, high-pressure refrigerant is circulated through a heat exchanger, called a condenser, where it is cooled by heat transfer to the surrounding environment. As a result, the refrigerant condenses from a gas back to a liquid. After leaving the condenser, the refrigerant passes through a throttling device where the pressure and the temperature are reduced. The cold refrigerant leaves the throttling device and enters a second heat exchanger, called an evaporator, located in or near the refrigerated space. Heat transfer with the evaporator and the refrigerated space causes the refrigerant to evaporate or to change from a saturated mixture of liquid and vapor into a superheated vapor. The vapor leaving the evaporator is then drawn back into the compressor so as to repeat the refrigeration cycle.
Attempts to use such a Rankine cycle system to refrigerate a portable device, however, have been largely unsuccessful. The typical components of a Rankine cycle system are generally too large, too heavy, and too loud. Further, such systems generally contain noxious or greenhouse gases. As a result, most Rankine cycle systems are used for stationary refrigeration devices.
Similarly, attempts have been made to use the waste heat generated in a Rankine cycle system to provide heat to a warming compartment spaced apart from the refrigeration area. Although waste heat is generated, the relatively large and cumbersome configuration required by a Rankine cycle system, may make it difficult to transfer effectively the waste heat to the warming compartment. Separating the refrigeration components and the warming compartment generally may lessen the efficiency of the system as a whole.
One alternative to the use of a Rankine cycle system is a Stirling cycle cooler. The Stirling cycle cooler is also a well-known heat transfer mechanism. Briefly described, a Stirling cycle cooler compresses and expands a gas (typically helium) to produce cooling. This gas shuttles back and forth through a regenerator bed to develop much greater temperature differentials than may be produced through the normal Rankine compression and expansion process. Specifically, a Stirling cooler may use a displacer to force the gas back and forth through the regenerator bed and a piston to compress and expand the gas. The regenerator bed may be a porous element with significant thermal inertia. During operation, the regenerator bed develops a temperature gradient. One end of the device thus becomes hot and the other end becomes cold. See David Bergeron, Heat Pump Technology Recommendation for a Terrestrial Battery-Free Solar Refrigerator, September 1998. Patents relating to Stirling coolers include U.S. Pat. Nos. 5,678,409; 5,647,217; 5,638,684; 5,596,875 and 4,922,722, all incorporated herein by reference.
Stirling cooler units are desirable because they are nonpolluting, efficient, and have very few moving parts. The use of Stirling coolers units has been proposed for conventional refrigerators. See U.S. Pat. No. 5,438,848, incorporated herein by reference. The integration of a free-piston Stirling cooler into a conventional refrigerated cabinet, however, requires different manufacturing, installation, and operational techniques than those used for conventional compressor systems. See D. M. Berchowitz et al., Test Results for Stirling Cycle Cooler Domestic Refrigerators, Second International Conference. As a result, the use of the Stirling coolers in refrigerators or similar devices is not well known.
Likewise, the use of Stirling coolers in portable refrigeration devices is not well known to date. Further, the use of Stirling coolers to heat and to cool simultaneously separate compartments of a device is not known. A need exists therefore for adapting Stirling cooler technology to portable refrigeration and heating devices.
The present invention thus provides for a device for heating a first article and cooling a second article. The device may include an enclosure with a hot compartment and a cold compartment. The device also may include a Stirling cooler with a hot end and a cold end. The hot end may be positioned in communication with the hot compartment so as to heat the first article and the cold end may be positioned in communication with the cold compartment so as to cool the second article.
Specific embodiments of the present invention include the use of an insulated divider positioned between the hot compartment and the cold compartment. The Stirling cooler may include a regenerator positioned between the hot end and the cold end. The regenerator may be positioned within the insulated divider. The enclosure may include a handle for carrying the enclosure.
The cold end of the Stirling cooler may include a cold end heat exchanger. The cold compartment may include a Stirling cooler section with a fan, a product section with a product support for positioning the second article thereon, and an airflow path for circulating air through the Stirling cooler section and the product section. The product support may include a number of apertures therein in communication with the airflow path.
The cold compartment may include a sensor for determining the temperature therein. The sensor may be in communication with a controller. The enclosure may include an external vent positioned adjacent to the cold compartment. The controller may be in communication with the external vent so as to open the vent when the temperature within the cold compartment drops below a predetermined temperature.
The cold compartment also may include a divider positioned between the Stirling cooler section and the product section. The divider may include an internal vent therein. The internal vent may include a first internal vent positioned on a first side of the divider and a second internal vent positioned on a second side of the divider. The enclosure may include a number of external vents positioned adjacent to the cold compartment. The controller may be in communication with the internal vent and the external vents so as to close the internal vent and so as to open the external vents when the temperature within the cold compartment drops below a predetermined temperature and the ambient temperature is below freezing.
The hot end of the Stirling cooler may include a hot end heat exchanger. The hot compartment may include a Stirling cooler section with a fan, a product section with a product support for positioning the first article thereon, and an airflow path for circulating air through the Stirling cooler section and the product section. The hot compartment may include a sensor for determining the temperature therein. The enclosure may include an external vent positioned adjacent to the hot compartment. The sensor may be in communication with the external vent so as to open the vent when the temperature within the hot compartment rises above a predetermined temperature.
The device may further include a wick extending from about the cold end of the Stirling cooler in the cold compartment to about the hot end of the Stirling cooler in the hot compartment. The cold compartment may include a condensate collector positioned adjacent to the cold end of the Stirling cooler and the wick so as to collect condensate and wick it to the hot compartment.
A further embodiment of the present invention may provide for a Stirling cooler driven device for use with ambient temperatures above and below freezing. The device may include an enclosure. The enclosure may include a Stirling cooler section for positioning the Stirling cooler therein, a product section, and a divider positioned therebetween. The divider may include an internal vent. The enclosure may include a number of external vents positioned adjacent to the Stirling cooler section.
The device also may include an internal temperature sensor positioned within the enclosure and an external temperature sensor positioned on the enclosure. The sensors may be in communication with a controller. The controller may open at least a first one of the external vents when the temperature within the enclosure drops below a predetermined temperature and the ambient temperature is above freezing. The controller may close the internal vent and open the external vents when the temperature within the enclosure drops below the predetermined temperature and the ambient temperature is below freezing. The predetermined temperature may be below about thirty-two degrees Fahrenheit (zero degrees Celsius).
A further embodiment of the present invention may provide for a device for heating a first article with a hot end of a Stirling cooler and cooling a second article with a cold end of the Stirling cooler. The device may include a hot compartment with the hot end of the Stirling cooler positioned therein and a cold compartment with the cold end of the Stirling cooler positioned therein. A hot compartment vent may be positioned adjacent to the hot compartment and a cold compartment vent may be positioned adjacent to the cold compartment. A hot compartment sensor may be positioned within the hot compartment. The hot compartment sensor may be in communication with the hot compartment vent so as to open the vent when the temperature within the hot compartment rises above a first predetermined temperature. A cold compartment sensor may be positioned within the cold compartment. The cold compartment sensor may be in communication with the cold compartment vent so as to open the vent when the temperature within the cold compartments falls below a second predetermined temperature.
A further embodiment of the present invention provides for a temperature-controlled device for use with an electrical receptacle of a vehicle. The device may include a portable enclosure. The portable enclosure may have an interior space to be heated or cooled, a Stirling cooler positioned about the enclosure for providing heating or cooling to the interior space, and an electrical line for powering the Stirling cooler via the electrical receptacle.
A further embodiment of the present invention may provide for a heating and cooling device. The device may include an enclosure with a Stirling cooler, a hot compartment, and a cold compartment. The Stirling cooler may have a hot end heat exchanger positioned in communication with the hot compartment and a cold end heat exchanger positioned in communication with the cold compartment. The hot compartment may include a fan positioned adjacent to the hot end heat exchanger. The cold compartment may include a condensate collector positioned adjacent to the cold end heat exchanger so as to collect condensate from the cold end heat exchanger. The device also may include a wick. The wick may extend from the condensate collector in the cold compartment to the hot compartment so as to wick condensate from the condensate collector to the hot compartment and so as to evaporate the condensate via an air stream produced by the fan.
A further embodiment of the present invention may provide for a transportable apparatus. The apparatus may include an insulated enclosure for containing a number of containers. The enclosure may be mountable in a vehicle. A dispensing path therein may be defined by a pair of spaced members. The apparatus also may include a Stirling cooler. The Stirling cooler may be powerable by the vehicle""s electrical system. The enclosure may have an inside, an outside, and an outlet for dispensing the containers. The dispensing path may include a first member positioned adjacent to the outlet such that the containers in the dispensing path contact the first member before being dispensed through the outlet. The Stirling cooler may include a hot portion and a cold portion. The cold portion of the Stirling cooler may be in heat transfer relationship with the first member. A second member may be connected in heat transfer relationship to the first member and to the cold portion of the Stirling cooler.
A method of the present invention may include powering a Stirling cooler by a vehicle""s electrical system and contacting at least a portion of a container to be dispensed from an insulated enclosure with a heat-conducting member before the container is dispensed from the enclosure. Heat then may be transferred from the container to the heat-conducting member to a cold portion of the Stirling cooler.
A further method of the present invention may include contacting at least a portion of a container to be dispensed from an insulated enclosure disposed in a vehicle with a heat-conducting member before the container is dispensed from the enclosure. Heat may then be transferred from the container to the heat-conducting member to a cold portion of a Stirling cooler. The Stirling cooler being powered by an electrical system of the vehicle.
A further embodiment of the present invention may provide for a transportable apparatus for containing a number of containers. The apparatus may include an insulated enclosure. The enclosure may be positioned within a vehicle having an electrical system. A Stirling cooler may be positioned in communication with the enclosure. The Stirling cooler may be in communication with the electrical system. The insulated enclosure may include a dispensing path with one or more doors. The Stirling cooler may include a cold end and a hot end. A plate may be in communication with the cold end and at least part of the dispensing path. The cold end or the hot end may be in communication with the enclosure.
Other objects, features, and advantages of the present invention will become apparent upon review of the following specification, when taken in conjunction with the drawings and the appended claims.